What WordPress Hook Is Used Before Signup Data is Saved?

This one?

do_action( 'register_post', $sanitized_user_login, $user_email, $errors );

http://phpxref.ftwr.co.uk/wordpress/nav.html?wp-login.php.source.html line 316

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)